1. Technical Field
The present invention relates to a heat resistant hydrogen separation membrane and a method for manufacturing the same, and more specifically, to a hydrogen separation membrane having a configuration in which granular ceramic is coated on a surface of a porous metal support and hydrogen permeable metal is coated thereon to improve durability, and a method for coating the same. The present invention provides a hydrogen separation membrane with improved durability and heat resistance by inhibiting inter-diffusion between the porous metal support and a separation material through the above-described configuration.
2. Background Art
A separation device is necessary to obtain hydrogen from hydrogen mixed gas, and purification of hydrogen is possible by using a variety of separation processes using pressure swing adsorption (PSA), subzero cooling, a separation membrane, or a getter. Since there is an advantage of high energy efficiency by configuring a process using a separation membrane in the hydrogen purification technique, a lot of research is under way in this field.
The separation membrane may be largely divided into a foil-type film or a coating film prepared by coating a surface of a porous support with dense materials.
Because the hydrogen penetration rate is increased in inverse proportion to a thickness of a separation layer, most studies relate to thin film coating on the surface of the porous support. In particular, because separation materials are expensive compared to the support, hydrogen flux may be improved and costs thereof may be reduced by the thin film coating. For this reason, many studies have progressed in the related art (see Korean Patent Application No 10-2009-0121865).
The porous support is classified into ceramic and metal supports. Since the ceramic support is un-reactive with the coated separation layer, stable characteristics may be obtained, while when the coating film is modularized, sealing and bonding properties may be deteriorated. On the other hand, the metal support has benefits in terms of adhesiveness and characteristics for easy modularization, but has a problem in which diffusion between the coating layer for separating hydrogen and the support may occur, and thereby decrease durability.
In order to overcome the above-described shortcomings, there are efforts to inhibit inter-diffusivity by performing sol-gel coating on the surface of the porous support to form a ceramic coating layer thereon, which may be found in the related art (see Lee Kew-Ho, Seung-Eun Nam, Hydrogen separation by Pd alloy composite membranes: introduction of diffusion barrier, J. Membr. Sci., 2001, 192, 177-185, Lee Kew-Ho et al, Study on the variation of morphology and separation behavior of the stainless steel supported membranes at high temperature, J. Membr. Sci., 2003, 220, 137-153).
However, the above-described process has a difficulty in reproducible manufacturing of the support due to a poor adhesive force between the metal support and ceramic materials coated thereon. Therefore, this restriction acts as one of the biggest challenges when manufacturing the separation membrane by using the porous metal support.
As described above, in order to form a coating film on the porous metal support with the potential for easy modularization, inhibition of diffusion between the support and the coating layer, as well as developments for the surface porous enhancing technique are essentially required, but this has still not been completed.